FFMPEG Warning : Found yasm 1.x.x.xx Minimum version is Yasm-1.0.0
July 25 2015
Found yasm 1.x.x.xxxx
Minimum version is yasm-1.0.0
If you really want to compile without asm, configure with --disable-asm.
that means that you have installed old version of yasm, so you need to update latest one with following commands,